I was so excited when I saw that Bestbuy dropped the price for the MDR-XB500 ($50) that I ran out and both a pair yesterday. I have been wanting them for a while.
I have to say that so far I am a bit dissapointed. I do like bass, but they seem rather muddy. They are very light and comfortable, but I found the sound somewhat painful, I don't know why. Too much bass? too much treble?

I think I'm taking them back tomorrow. I will stick with my modded JVC HA-RX900s. They are a bit big and heavy, but they sound wayyyy better than the Sonys.